Octahedrally coordinated single layered CaF₂: robust insulating behaviour

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Two-dimensional (2D) materials are crucial for next-generation electronics.
• Hexagonal boron nitride (h-BN) is a widely used insulating 2D material.
• Exploring novel 2D materials with superior properties is essential.

Purpose of the Study:

• Investigate the structural, vibrational, and electronic properties of single-layered calcium fluoride (CaF2).
• Assess the potential of 2D and 1D CaF2 nanostructures in nanoelectronics.

Main Methods:

• First-principles calculations were employed.
• Phonon dispersion analysis confirmed dynamical stability.
• Electronic band structure and density of states were computed.

Main Results:

• Single-layered 1T-CaF2 is dynamically stable and exhibits Raman active modes.
• 1T-CaF2 possesses an indirect wide band gap, exceeding that of h-BN.
• 1D CaF2 nanoribbons (zigzag and armchair) maintain the 1T phase and show robust insulating behavior.
• Properties are independent of nanoribbon width.

Conclusions:

• Single-layered CaF2 is a stable 2D material with promising electronic properties.
• Both 2D and 1D CaF2 nanostructures are potential alternatives to h-BN in nanoelectronic applications.
• CaF2 offers a wider electronic band gap compared to h-BN.